Methods and Systems for High Pressure Die Casting

ABSTRACT

Methods and systems for high pressure die casting with metal alloys of low silicon content are described. Metal alloys can be modified with nanoparticles to achieve high fluidity and hot cracking resistance to be compatible with high pressure die casting. The die cast metal parts have high strength, high ductility, and high thermal and electrical conductivity. The die cast metal parts can be anodized with different colors.

CROSS-REFERENCE TO RELATED APPLICATIONS

The current application claims the benefit of and priority to U.S.Provisional Patent Application No. 63/268,049 entitled “Methods andSystems for High Pressure Die Casting” filed Feb. 15, 2022. Thedisclosure of U.S. Provisional Patent Application No. 63/268,049 ishereby incorporated by reference in its entirety for all purposes.

FIELD OF THE INVENTION

The present invention generally relates to methods and systems for highpressure die casting with metal alloys of low silicon content; and moreparticularly to methods and systems for high pressure die casting withlow silicon content metal alloys modified with nanoparticles.

BACKGROUND OF THE INVENTION

Die cast metal alloys have applications in various industries. Die castmetal alloys generally require both high strength and ductility. Metalalloys should also have good castability and heat cracking resistance tobe suitable for high pressure die casting processes. Traditionally,silicon has been added to metal alloys, such as aluminum alloys, toimprove the fluidity of metal alloys to be compatible with high pressuredie casting. However, high silicon content may deteriorate ductility,thermal conductivity, electrical conductivity, and anodizing capabilityof metal alloys. Metal alloys with uncompromised ductility andconductivities, that are also suitable for high pressure die castingprocesses may be desired.

BRIEF SUMMARY OF THE INVENTION

Methods and systems for high pressure die casting with metal alloys oflow silicon content modified with nanoparticles are illustrated.

An embodiment of the invention includes a metal alloy for high pressuredie casting, comprising a metal alloy selected from the group consistingof an aluminum alloy, a magnesium alloy, a copper alloy, and a zincalloy; and at least one type of nanoparticle dispersed in the metalalloy; wherein the metal alloy comprises less than 4.0 wt. % silicon;and wherein the metal alloy is compatible with a high pressure diecasting process.

In another embodiment, the metal alloy is selected from the groupconsisting of A201, AA2024, A206, AA2618, AA5083, AA6013, AA6061,AA6063, AA6069, AA7034, AA7050, AA7075, and AA7068.

In an additional embodiment, the at least one type of nanoparticle isselected from the group consisting of a metal oxide, a non-metal oxide,a metal carbide, a non-metal carbide, a metal silicide, a metal boride,a metal nitride, and any combinations thereof.

In a further embodiment, the at least one type of nanoparticle has astructure of a core-shell particle.

In another embodiment, the nanoparticle comprises less than 30 vol. % ofthe metal alloy.

In a further yet embodiment, the nanoparticle comprises 0.1 vol. % to 2vol. % of the metal alloy.

In yet another embodiment, the metal alloy comprises AA6061 and thenanoparticle comprises TiC, and the TiC nanoparticle comprises 1.0 vol.% of the metal alloy.

In a further embodiment again, the high pressure die casting processuses a pressure between 30 MPa and 100 MPa.

In an additional embodiment, the high pressure die casting process usesa pressure greater than 100 MPa.

In another embodiment again, the high pressure die casting processcomprises a cooling step with a cooling rate between 100° C./s and 300°C./s.

A further embodiment includes a method for high pressure die castingcomprising:

-   -   providing a metal alloy modified with at least one type of        nanoparticle, wherein the metal alloy comprises a silicon weight        concentration of less than 4.0%;    -   melting the metal alloy and filling a die with the molten metal        alloy under a pressure, wherein the pressure is compatible with        the high pressure die casting process; and    -   cooling the die to solidify the molten metal alloy.

In a further yet embodiment, the method further comprising anodizing thedie cast metal alloy with at least one color.

In another embodiment, the metal alloy is selected from the groupconsisting of an aluminum alloy, a magnesium alloy, a copper alloy, anda zinc alloy.

In an additional embodiment, the metal alloy is selected from the groupconsisting of A201, AA2024, A206, AA2618, AA5083, AA6013, AA6061,AA6063, AA6069, AA7034, AA7050, AA7075, and AA7068.

In another yet embodiment, the at least one type of nanoparticle isselected from the group consisting of a metal oxide, a non-metal oxide,a metal carbide, a non-metal carbide, a metal silicide, a metal boride,a metal nitride, and any combinations thereof.

In a further yet embodiment, the at least one type of nanoparticle has astructure of a core-shell particle.

In an additional embodiment, the at least one type of nanoparticlecomprises less than 30 vol. % of the metal alloy.

In another embodiment again, the nanoparticle comprises 0.1 vol. % to 2vol. % of the metal alloy.

In a further embodiment, the metal alloy comprises AA6061 and thenanoparticle comprises TiC, and the TiC nanoparticle comprises 1.0 vol.% of the metal alloy.

In another embodiment again, the die cast metal alloy as formed has aelongation equal to or less than 30% and an ultimate tensile strengthgreater than 500 MPa.

In an additional embodiment again, the die cast metal alloy has athickness of at least 0.2 mm.

In a further yet embodiment, the pressure is between 30 MPa and 100 MPa.

In yet another embodiment, the pressure is greater than 100 MPa.

In another embodiment, the die is cooled with a cooling rate between100° C./s and 300° C./s.

In a further embodiment again, the method further comprising a postprocess of the die cast metal alloy.

In an additional embodiment, the post process is selected from the groupconsisting of: a T5 treatment, a natural aging treatment, and a T6treatment.

Another embodiment includes a high pressure die cast metal partcomprising a metal alloy; and at least one type of nanoparticledispersed in the metal alloy; wherein the metal alloy comprises lessthan 4.0 wt. % silicon; wherein the metal part is produced via a highpressure die casting process; and wherein the die cast metal part has athickness of at least 0.2 mm.

In a further embodiment, the metal alloy is selected from the groupconsisting of an aluminum alloy, a magnesium alloy, a copper alloy, anda zinc alloy.

In an additional embodiment, the metal alloy is selected from the groupconsisting of A201, AA2024, A206, AA2618, AA5083, AA6013, AA6061,AA6063, AA6069, AA7034, AA7050, AA7075, and AA7068.

In another embodiment again, the at least one type of nanoparticle isselected from the group consisting of a metal oxide, a non-metal oxide,a metal carbide, a non-metal carbide, a metal silicide, a metal boride,a metal nitride, and any combinations thereof.

In a further embodiment again, the at least one type of nanoparticle hasa structure of a core-shell particle.

In a further yet embodiment, the nanoparticle comprises less than 30vol. % of the metal alloy.

In yet another embodiment, the nanoparticle comprises 0.1 vol. % to 2vol. % of the metal alloy.

In a further embodiment, the metal alloy comprises AA6061 and thenanoparticle comprises TiC, and the TiC nanoparticle comprises 1.0 vol.% of the metal alloy.

In another embodiment again, the high pressure die casting process usesa pressure between 30 MPa and 100 MPa.

In yet another embodiment, the high pressure die casting process uses apressure greater than 100 MPa.

In a further embodiment again, the high pressure die casting processcomprises a cooling step with a cooling rate between 100° C./s and 300°C./s.

In an additional embodiment, the metal part is anodized with at leastone color.

Another embodiment includes a method for improving castibility of ametal alloy comprising incorporating at least one type of nanoparticleinto a metal alloy; wherein the metal alloy comprises less than 4.0 wt.% silicon; wherein the nanoparticle comprises less than 30 vol. % of themetal alloy; and wherein the metal alloy is compatible with a highpressure die casting process.

In a yet further embodiment, the metal alloy selected from the groupconsisting of an aluminum alloy, a magnesium alloy, a copper alloy, anda zinc alloy.

In an additional embodiment, the metal alloy is selected from the groupconsisting of A201, AA2024, A206, AA2618, AA5083, AA6013, AA6061,AA6063, AA6069, AA7034, AA7050, AA7075, and AA7068.

In another yet embodiment, the at least one type of nanoparticle isselected from the group consisting of a metal oxide, a non-metal oxide,a metal carbide, a non-metal carbide, a metal silicide, a metal boride,a metal nitride, and any combinations thereof.

In a further embodiment, the at least one type of nanoparticle has astructure of a core-shell particle.

In a yet further embodiment, the nanoparticle comprises 0.1 vol. % to 2vol. % of the metal alloy.

In another embodiment again, the metal alloy comprises AA6061 and thenanoparticle comprises TiC, and the TiC nanoparticle comprises 1.0 vol.% of the metal alloy.

In yet another embodiment, the high pressure die casting process uses apressure between 30 MPa and 100 MPa.

In an additional embodiment again, the high pressure die casting processuses a pressure greater than 100 MPa.

In another yet embodiment again, the high pressure die casting processcomprises a cooling step with a cooling rate between 100° C./s and 300°C./s.

Additional embodiments and features are set forth in part in thedescription that follows, and in part will become apparent to thoseskilled in the art upon examination of the specification or may belearned by the practice of the disclosure. A further understanding ofthe nature and advantages of the present disclosure may be realized byreference to the remaining portions of the specification and thedrawings, which forms a part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The description will be more fully understood with reference to thefollowing figures, which are presented as exemplary embodiments of theinvention and should not be construed as a complete recitation of thescope of the invention. It should be noted that the patent orapplication file contains at least one drawing executed in color. Copiesof this patent or patent application publication with color drawing(s)will be provided by the Office upon request and payment of the necessaryfee.

FIG. 1 illustrates a high pressure die casting process in accordancewith an embodiment of the invention.

FIG. 2A illustrates a high pressure die cast AA6061 part withoutnanoparticles in accordance with an embodiment of the invention.

FIG. 2B illustrates a high pressure die cast AA6061 part with 1.0 vol. %TiC nanoparticles in accordance with an embodiment of the invention.

FIGS. 3A-3D illustrate colored die cast AA6061 parts with 1.0 vol. %nanoparticles after anodizing.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the drawings, methods and systems for high pressure diecasting using low silicon content metal alloys are described. Manyembodiments provide low silicon content metal alloys including (but notlimited to) aluminum alloys modified with nanoparticles for highpressure die casting processes. Die casting processes in accordance withsome embodiments produce high strength, high ductility, and high thermalconductivity metal parts. Certain embodiments provide die cast metalparts can be anodized to produce parts of desired colors. Severalembodiments provide that the nanoparticles can enhance the fluidity ofaluminum alloys under high pressure, and avoid issues including (but notlimited to) die-sticking and hot cracking during die casting. Thenanoparticle modified metal alloys in accordance with certainembodiments allow die cast high performance metal alloys that containlow or no silicon contents. High performance aluminum alloys with lowsilicon contents are traditionally impossible to die cast due toproblems such as hot cracking. Die cast metal alloys with low siliconcontent in accordance with some embodiments can enable mass productionof aluminum alloys with high strength, excellent ductility and thermalconductivity. Many embodiments provide that the aluminum alloys with lowsilicon contents would allow good anodizing capability to offer colorfulparts. In a number of embodiments, the combination of strength andductility may allow the die cast metal parts for structural components.In certain embodiments, the high thermal conductivity of the die castaluminum parts, in addition to the good strength and ductility, mayallow efficient thermal management in applications including (but notlimited to) heat sinks and exchangers.

Normally, nanoparticles may increase the viscosity of molten metalalloys, which may not be ideal for high pressure die filling and rapidcooling processes during die casting. However, the nanoparticles inaccordance with many embodiments enable die casting of high performancealloys including (but not limited to) high-performance wrought and castaluminum alloys, with a silicon content from about 0 wt % to about 4.0wt % for structural applications. Several embodiments provide thatnanoparticles can simultaneously enhance the fluidity of alloys andeliminate hot cracking during rapid cooling. The enhanced fluidity ofmetal alloys in accordance with certain embodiments can be compatiblewith die filling processes under high pressure. In various embodiments,the pressure for the die casting process can range from about 30 MPa toabout 100 MPa; or lower than about 30 MPa; or higher than about 100 MPa.As can readily be appreciated, any of a variety of pressure can beutilized as appropriate to the requirements of specific applications inaccordance with various embodiments of the invention.

Many embodiments provide that metal alloys being resistant to hotcracking can stand cooling processes with a high cooling rate. Inseveral embodiments, the cooling rate can be from about 100° C./s toabout 300° C./s; or lower than about 100° C./s; or higher than about300° C./s. As can readily be appreciated, any of a variety of coolingrate can be utilized as appropriate to the requirements of specificapplications in accordance with various embodiments of the invention.

The improved fluidity and castability of metal alloys by nanoparticlesin accordance with certain embodiments enable to die cast metal partwith a thickness from about 0.2 mm to about 0.5 mm; or a thicknessgreater than about 0.5 mm.

In several embodiments, die cast metal alloys have ductility and/orelongation of less than or equal to about 20%; or less than or equal toabout 30%. In some embodiments, die cast metal alloys can have strengthof greater than or equal to about 500 MPa. The thermal conductivity ofdie cast metal alloys can be less than or equal to about 230 W/mw; orgreater than about 230 W/mw; in accordance with a number of embodiments.The ductility, strength, and thermal conductivity are measured for ascast metal alloys without post processing.

In several embodiments, die cast metal parts can be anodized to add anydesired color(s). Examples of anodized colors include (but are notlimited to): red, blue, pink, gold, yellow, green, and any combinationsthereof. As can readily be appreciated, any of a variety of color can beutilized as appropriate to the requirements of specific applications inaccordance with various embodiments of the invention.

For the purpose of this invention, the term “die casting” can also beinterpreted to “high pressure die casting”, except where otherwisenoted.

High pressure die casting processes in accordance with variousembodiments of the invention are discussed further below.

High Pressure Die Casting

Die casting can be an economical mass production method for metal parts.During the die casting processes, molten metal can be injected into amold under high pressure before solidification at a high cooling rate(ranging from about tens of degree Celsius per second to about hundredsof degree Celsius per second). The applied pressure can be hydraulic orpneumatic pressure. This pressure can be maintained until the castingsolidifies. The molds, known as dies, can be made from high quality toolsteel, can produce geometrically complex parts, and lend high degrees ofaccuracy and repeatability to the processes. The high pressure fillingof the die in high pressure die casting may allow the molten alloy to beinjected quickly and, enable automated processes with high productivity.

In comparison to gravity die casting (also known as permanent moldcasting), the molten metal is poured into the mold from above purelyunder gravitational force. As gravity die casting relies on gravity tofill the mold, the process can be slower and therefore less suited formass production runs.

High pressure die casting can have advantages including (but not limitedto) high dimensional accuracy, smooth cast surfaces, reducing oreliminating secondary machining operations, rapid production rates, etc.However, one disadvantage for high pressure die casting is that theprocess is limited to metals with high fluidity. As the injectionprocess is under high pressure (from about 30 MPa to about 100 MPa) andthe molten alloy is solidified at a high cooling rate (from about tensto hundreds of degree Celsius per second), low fluidity molten alloysand/or high viscosity molten alloys may clog the mold cavity so as toaffect the accuracy of the cast part. In addition to high fluidity,alloys suitable for high pressure die casting should have goodresistance to cracking under high pressure and high cooling rate.

Anodizing is a process in which alloy parts are used as anode andstainless steel, chromium, or conductive electrolyte are used as thecathode in the proper electrolyte. Under certain voltage and currentconditions, the anode is oxidized to obtain anodized film on the surfaceof workpiece. Sulfuric acid anodizing may be used in the anodizing andcoloring process. Anodizing can provide colors and/or protective filmsfor the die cast alloys.

Metal Alloys for High Pressure Die Casting

Various types of metal alloys including (but not limited to) zinc alloy,aluminum alloy, copper alloy, and tin alloy, can be used in highpressure die casting. Aluminum alloys have been widely used in consumerelectronics, automotive, aerospace, ship building and other fields dueto its plasticity, corrosion resistance and light weight. Die castaluminum parts find wide applications in industries including computerdevices, communication devices, consumer electronics, automobiles,buildings, windows, aerospace, and sports. Since high pressure diecasting often operates at a high cooling rate at tens to hundreds ofdegree Celsius per second for metals, the fluidity and hot crackingresistance of the alloys can be crucial for the integrity of parts,especially for thin wall structures. Traditionally high performancealuminum alloys including (but not limited to) A201, AA2024, A206,AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA7034, AA7050, AA7075,and AA7068 offer good strength, ductility, and fatigue life, as well asanodizing capability and thermal conductivity. Unfortunately, thesealloys are not suited for die casting due to low fluidity and hotcracking issues.

Al—Si alloys are one of the most popular die cast aluminum alloys.Silicon may help alloy fluidity largely due to its high heat ofcrystallization. As silicon solidifies, a large amount of heat may bereleased to reheat liquid aluminum, enhancing the melt fluidity. For diecast alloys, a silicon content above 4.5 wt % (often ranging from about8 wt % to about 13 wt %) and adequate alloying elements including (butnot limited to) Fe and/or Mn are added to ensure high fluidity and hotcracking resistance. Thus, die casting aluminum alloy and die castingparts generally contain silicon content higher than about 4.5 wt %.Examples of Al—Si alloys suitable for die casting include (but are notlimited to): AA360, A360, AA380, AA383, AA384, B390, AA413, A413, andC443.

However, the silicon phase in the Al—Si alloys would appear gray orblack after anodizing, and the anodized alloy and/or parts may appear ina dark color, which can be undesirable in many applications withcosmetics requirements. With the increase of silicon content, the colorof the anodized film changes from light gray to dark gray to black-gray.Therefore, cast aluminum alloy with high silicon content may not besuitable for anodizing. Moreover, the high content of silicon and otherelements used to tackle fluidity and hot cracking in aluminum diecasting alloys can deteriorate the ductility and thermal conductivityand/or electrical conductivity of the aluminum alloys after die casting.

There are some aluminum alloy systems with low silicon content. Oneexample of aluminum alloy with low silicon content includes Al—Mgsystems, such as AA 518, Al-8Mg. Another example of low silicon aluminumalloy includes Al—Mg—Si systems. Al—Mg—Si systems can include 2 wt %-5.5wt % Mg, 1.5 wt %-3 wt % Si, trace of Mn, trace of Fe, with the balancebeing Al. Examples of Al—Mg—Si system alloys include (but are notlimited to) Magsimal-59, C446, Aural-11, Calypso 53 and 54SM. However,these aluminum alloys with low silicon content can be difficult to diecast due to low fluidity and high cracking tendency. In addition, suchalloys can be very sensitive to wall thickness, especially thin walls.Furthermore, the low silicon aluminum alloy may require toxic Be as anadditive, and can be susceptible to hot tear and stress corrosioncracking. Moreover, their thermal conductivity may be low due to thealloy contents.

Table 1 below reproduced from North American Die Casting Association(NADCA) includes chemical compositions of various Al—Si alloys and anAl-8Mg alloy used in high pressure die casting. All single values aremaximum composition percentages unless otherwise stated.

TABLE 1 Aluminum Die Casting Alloy Compositions. Aluminum Die CastingAlloys {circle around (A)}{circle around (E)} Commercial: 360 A360    380{circle around (B)}   A380{circle around (B)}   383 384{circle around(B)}  B390*    13 A13    43 218 ANSI/AA 360.0 A360.0   380.0   A380.0  383.0 384.0  B390.0   413.0 A413.0   C443.0 518.0 Nominal Mg 0.5 Mg 0.5Cu 3.5 Cu 3.5 Cu 2.5 Cu 3.8 Cu 4.5 Si 12.0 Si 12.0 Si 5.0 Mg 8.0 Comp:Si 9.0 Si 9.5 Si 8.5 Si 8.5 Si 10.5 Si 11.0 Si 17.0 Detailed CompositionSilicon 9.0-10.0 9.0-10.0 7.5-9.5 7.5-9.5 9.5-11.5 10.5-12.0 16.0-18.011.0-13.0 11.0-13.0 4.5-6.0 0.35 Si Iron 2.0 1.3  2.0  1.3  1.3 1.3 1.3  2.0 1.3  2.0 1.8 Fe Copper 0.6 0.6  3.0-4.0 3.0-4.0 2.0-3.0 3.0-4.54.0-5.0 1.0 1.0  0.6 0.25 Cu Magnesium 0.4-0.6  0.4-0.6    0.30{circlearound (F)}   0.30{circle around (F)} 0.10 0.10 0.45-0.65 0.10 0.10 0.107.5-8.5 Mg Manganese 0.35 0.35 0.50 0.50 0.50 0.50 0.50 0.35 0.35 0.350.35 Mn Nickel 0.50 0.50 0.50 0.50 0.30 0.50 0.10 0.50 0.50 0.50 0.15 NiZinc 0.50 0.50 3.0  3.0  3.0 3.0  1.5  0.50 0.50 0.50 0.15 Zn Tin 0.150.15 0.35 0.35 0.15 0.35 — 0.15 0.15 0.15 0.15 Sn Titanium — — — — — —0.10 — — — — Ti Others — — — — — — 0.10 — — — — Each Total 0.25 0.250.50 0.50 0.50 0.50 0.20 0.25 0.25 0.25 0.25 Others {circle around (C)}Aluminum Balance Balance Balance Balance Balance Balance Balance BalanceBalance Balance Balance Al

Table 2 from NADCA reproduced below includes mechanical properties ofaluminum alloys used in high pressure die casting. Typical values basedon “as-cast” characteristics for separately die cast specimens, notspecimens cut from production die castings.

TABLE 2 Aluminum Die Casting Alloy Properties. Aluminum AlloysDesignation 360.0 A360.0 380.0 A380.0 383.0 384.0 B390.0 413.0 A413.0C443.0 518.0 Mechanical Properties Ultimate Tensile Strength ksi 44 4646 47 45 48 46 43 42 33 45 (MPa) (300) (320) (320) (320) (310) (330)(320) (300) (290) (230) (310) Tensile Yield Strength {circle around (A)}ksi 25 24 23 23 22 24 36 21 19 14 29 (MPa) (170) (170) (160) (160) (150)(170) (250) (140) (130) (100) (190) Compressive Yield Strength {circlearound (B)} ksi — — — — — — — — — — — (MPa) Elongation % in 2 in. 2.53.5 3.5 3.5 3.5 2.5 <1 2.5 3.5 9.0 5.0 (51 mm) Hardness BHN 75{circlearound (C)} 75{circle around (C)} 80{circle around (C)} 80{circle around(C)} 75{circle around (C)} 85{circle around (C)} 120{circle around (C)}80{circle around (C)} 80{circle around (C)} 65{circle around (C)}80{circle around (C)} Shear Strength ksi 28 26 28 27 — 29 — 25 25 19 29(MPa) (190) (180) (190) (190) (200) (170) (170) (130) (200) ImpactStrength Ft-lb — — 3 — 3{circle around (F)} — — — — — 7 (J) (4) (4) (9)Fatigue Strength ksi 20{circle around (D)} 18{circle around (D)}20{circle around (D)} 20{circle around (D)} 21{circle around (D)}20{circle around (D)} 20{circle around (D)} 19{circle around (D)}19{circle around (D)} 17{circle around (D)} 20{circle around (D)} (MPa)(140) (120) (140) (140) (145) (140) (140) (130) (130) (120) (120)Young's Modulus psi × 10⁶ 10.3 10.3 10.3 10.3 10.3 — 11.8 10.3 — 10.3 —(GPa) (71) (71) (71) (71) (71) (81.3) (71) (71) Physical PropertiesDensity lb/in³ 0.095 0.095 0.099 0.098 0.099 0.102 0.098 0.096 0.0960.097 0.093 (g/cm³) (2.63) (2.63) (2.74) (2.71) (2.74) (2.82) (2.73)(2.66) (2.66) (2.69) (2.57) Melting Range ° F. 1035-1105 1035-11051000-1100 1000-1100 960-1080 960-1080 950-1200 1065-1080 1065-10801065-1170 995-1150 (° C.) (557-596) (557-596) (540-595) (540-595)(516-582) (516-582) (510-650) (574-582) (574-632) (574-632) (535-621)Specific Heat BTU/lb° F. 0.230 0.230 0.230 0.230 0.230 — — 0.230 0.2300.230 — (J/kg° C.) (963) (963) (963 (963) (963) (963) (963) (963)Coefficient of Thermal Expansion μin./ 11.6 11.6 12.2 12.1 11.7 11.610.0 11.3 11.9 12.2 13.4 in. ° F. × 10⁻⁶ (21.0) (21.0) (22.0) (21.8)(21.1) (21.0) (18.0) (20.4) (21.6) (22.0) (24.1) (μm/m° K) ThermalConductivity BTU/ft hr° F. 65.3 65.3 55.6 55.6 55.6 55.6 77.4 70.1 70.182.2 55.6 (W/m° K) (113) (113) (96.2) (96.2) (96.2) (96.2) (134) (121)(121) (142) (96.2) Electrical Conductivity % IACS 30   29   27   23  23   22   27 31   31   37   24   Poisson's Ratio  0.33  0.33  0.33  0.33 0.33 — — — —  0.33 —

Table 3 from NADCA reproduced below includes mechanical properties ofmagnesium alloys, Zamak die casting alloys, and ZA die casting alloysused in high pressure die casting.

TABLE 3 Magnesium Alloys Zamak Die Casting Alloys ZA Die Casting AlloysAZ91D AM60B AS41B No. 2 No. 3 No. 5 No. 7 ZA-8 ZA-12 ZA-27 DesignationMechanical Properties Ultimate Tensile Strength 34 32 31 52 41 48 41 5459 62 ksi (230) (220) (215) (359) (283) (328) (283) (372) (400) (426)(MPa) Tensile Yield Strength {circle around (A)} 23 19 20 41 32 39 3241-43 45-48 52-55 ksi (160) (130) (140) (283) (221) (269) (221)(283-296) (310-331) (359-379) (MPa) Compressive Yield Strength {circlearound (B)} 24 19 20 93 60{circle around (M)} 87{circle around (M)}60{circle around (M)} 37 39 52 ksi (165) (130) (140) (641) (414) (600)(414) (252) (269) (358) (MPa) Elongation 3 6-8 6 7 10 7 13 6-10 4-72.0-3.5 % in 2 in. (51 mm) Hardness 75{circle around (C)} 62{circlearound (C)} 75{circle around (C)} 100{circle around (C)} 82{circlearound (C)} 91{circle around (C)} 80{circle around (C)} 100-103{circlearound (C)} 95-105{circle around (C)} 116-122{circle around (C)} BHNShear Strength 20 n/a n/a 46 31 38 31 40 43 47 ksi (140) (317) (214)(262) (214) (275) (296) (325) (MPa) Impact Strength 1.6{circle around(H)} 4.5{circle around (H)} 3.0{circle around (H)} 35{circle around (H)}43{circle around (H)} 48{circle around (H)} 43{circle around (H)}24-35{circle around (H)} 15-27{circle around (H)} 7-12{circle around(H)} ft-lb (2.2) (6.1) (4.1) (47.5) (58) (65) (58) (32-48) (20-37)(9-16) (J) Fatigue Strength 10{circle around (I)} 10{circle around (I)}n/a 8.5{circle around (D)} 6.9{circle around (D)} 8.2{circle around (D)}6.9{circle around (D)} 15{circle around (D)} — 21{circle around (D)} ksi(70) (70) (58.6) (47.6) (56.5) (47.6) (103) (145) (MPa) Young's Modulus6.5 6.5 6.5 {circle around (N)} {circle around (N)} {circle around (N)}{circle around (N)} 12.4 12 11.3 psi × 10⁶ (45) (45) (45) (85.5) (83)(77.9) (GPa) Physical Properties Density 0.066 0.065 0.064 0.24 0.240.24 0.24 0.227 0.218 0.181 lb/in³ (1.81) (1.79) (1.77) (6.6) (6.6)(6.7) (6.6) (6.3) (6.03) (5.00) (g/cm³) Melting Range 875-1105 1005-11401050-1150 715-734 718-728 717-727 718-728 707-759 710-810 708-903 ° F.(470-595) (540-615) (565-620) (379-390) (381-387) (380-386) (381-387)(375-404) (375-404) (375-484) (° C.) Specific Heat 0.25 0.25 0.24 0.100.10 0.10 0.10 0.104 0.107 0.125 BTU/lb° F. (1050) (1050) (1050) (419)(419) (419) (419) (435) (450) (525) (J/kg° C.) Coefficient of ThermalExpansion 13.8 14.2 14.5 15.4 15.2 15.2 15.2 12.9 13.4 14.4 μin./in. °F. × 10⁻⁶ (25.0) (25.6) (26.1) (27.8) (27.4) (27.4) (27.4) 23.2 (24.1)(26.0) (μm/m° K) Thermal Conductivity 41.8{circle around (J)} 36 40 60.565.3 62.9 65.3 66.3 67.1 72.5 BTU/ft hr° F. (72) (62) (68) (104.7) (113)(109) (113) (115) (116) (122.5) (W/m° K) Electrical Conductivity 10 11     25.0   27.0  26.0   27.0 27.7  28.3  29.7  % IACS   0.35 0.35  0.35   0.30    0.30   0.30    0.30 0.30 0.30 0.30 Poisson's RatioHigh Pressure Die Casting with Nanoparticles Modified Metal Alloys

In many embodiments, metal alloys modified with nanoparticles can enabledie casting of high performance metal alloys. In several embodiments,nanoparticle modified aluminum alloys have low or no silicon content.Some embodiments provide that nanoparticle modified in metal alloysallow high-performance wrought and cast alloys including (but notlimited to) aluminum alloys, with a low silicon content for structuralapplications. In certain embodiments, silicon content of nanoparticlemodified metal alloys is from about 0 wt. % to about 4.0 wt. %. As canreadily be appreciated, any of a variety of silicon content of less thanabout 4.0 wt. % can be utilized as appropriate to the requirements ofspecific applications in accordance with various embodiments of theinvention. Many embodiments provide that nanoparticles cansimultaneously enhance the fluidity of alloys (die-filling) andeliminate hot cracking under high cooling rate, without the addition ofa silicon content higher than about 4.0 wt %.

Several embodiments provide that metal alloys that can be modified withnanoparticles include at least one metal element including (but notlimited to) aluminum (Al), magnesium (Mg), iron (Fe), silver (Ag),copper (Cu), manganese (Mn), nickel (Ni), titanium (Ti), chromium (Cr),cobalt (Co), zinc (Zn), and alloys, mixtures, or other combinations oftwo or more of the foregoing metals, Al alloys, Mg alloys, Zn alloys,Ti—Al alloys, Al—Mg alloys, and Mg—Zn alloys, and alloys, mixtures, orother combinations of one or more of the foregoing metals with otherelements, such as steel (e.g., iron-carbon alloys oriron-chromium-carbon alloys). As can readily be appreciated, any of avariety of metal alloy can be utilized as appropriate to therequirements of specific applications in accordance with variousembodiments of the invention. Many embodiments make alloy systems thatare traditionally hard to die cast, suitable for die casting aftermodification with nanoparticles. In several embodiments, aluminumalloys, magnesium alloys, and zinc alloys can be modified withnanoparticles to adapt to high pressure die casting. A number ofembodiments provide that nanoparticle modified alloy systems for diecasting also have desired mechanical performance, thermal conductivity,and electrical conductivity. Examples of alloy systems include (but arenot limited to) A201, AA2024, A206, AA2618, AA5083, AA6013, AA6061,AA6063, AA6069, AA7034, AA7050, AA7075, and AA7068. As can readily beappreciated, any of a variety of alloy system can be utilized asappropriate to the requirements of specific applications in accordancewith various embodiments of the invention.

Many embodiments provide that nanoparticles are uniformly dispersed inthe metal alloy matrix. A number of embodiments provide that materialsfrom which the nanoparticles can be made include (but are not limitedto) ceramics, oxides, nitrides, borides, carbides and other carbon-basedparticles, metals and metal alloys, and core-shell particles. Specificexamples of the types of nanoparticles that may be dispersed in themetal matrices include aluminum oxide nanoparticles, aluminum nitridenanoparticles, carbon nanotubes, silicon carbide nanoparticles, siliconnitride nanoparticles, titanium carbide nanoparticles, titanium boridenanoparticles, titanium carbonitride nanoparticles, tungsten carbidenanoparticles, and core-shell particles. In addition, the nanoparticlescan be core-shell type nanoparticles that include a core material and acoating. Examples include SiC nanoparticles coated with SiO, and ceramicnanoparticles coated with a metal Such as nickel or silver. (See, e.g.,U.S. Pat. No. 9,023,128 B2 to Li et al., the disclosure of which isincorporated herein by reference in its entirety.)

In some embodiments, the nanoparticles can include one or more ceramics,although other nanoparticle materials are contemplated, including metalsor other conductive materials. Examples of suitable nanoparticlematerials include metal oxides (e.g., alkaline earth metal oxides,post-transition metal oxides, and transition metal oxides, such asaluminum oxide (Al₂O₃), magnesium oxide (MgO), titanium oxide (TiO₂),yttrium oxide (Y₂O₃), magnesium aluminate (MgAl₂O₄), and zirconium oxide(ZrO₂)), non-metal oxides (e.g., silicon oxide (SiO₂)), metal carbides(e.g., transition metal carbides, such as titanium carbide (TiC),niobium carbide (NbC), chromium carbide (Cr₃C₂), nickel carbide (NiC),hafnium carbide (HfC), vanadium carbide (VC), tungsten carbide (WC), andzirconium carbide (ZrC)), non-metal carbides (e.g., silicon carbide(SiC)), metal silicides (e.g., transition metal silicides, such astitanium silicide (Ti₅Si₃)), metal borides (e.g., transition metalborides, such as titanium boride (TiB₂), zirconium boride (ZrB₂),hafnium boride (HfB₂), vanadium boride (VB₂), and tungsten boride(W₂B₅)), metal nitrides (e.g., transition metal nitrides), core-shellparticles, metals (e.g., transition metals in elemental form such astungsten (W)), alloys, mixtures, or other combinations of two or more ofthe foregoing, and alloys, mixtures, or other combinations of one ormore of the foregoing with other elements. Particular examples ofsuitable nanoparticle materials include transition metal-containingceramics, where the presence of a transition metal can impart a greaterHamaker constant more closely approaching that of a metal matrix for areduced van der Waals potential well, such as transition metal carbides,transition metal silicides, transition metal borides, transition metalnitrides, and other non-oxide, transition metal-containing ceramics.(See, e.g., U.S. Pat. No. 11,040,395 B2 to Li et al., the disclosure ofwhich is incorporated herein by reference in its entirety.)

In many embodiments, the nanoparticles may have an average diameter ofless than about 500 nm. In some embodiments, the nanoparticles may havean average diameter of between about 1 nm and about 500 nm; betweenabout 1 nm and about 400 nm; between about 1 nm and about 300 nm;between about 1 nm and about 200 nm; between about 1 nm and about 100nm; between about 1 nm and about 70 nm; between about 1 nm and about 50nm; between about 1 nm and about 30 nm. Several embodiments provide thatthe distribution of sizes of the nanoparticles can be characterized by astandard deviation, relative to an average diameter, that is up to about100%, up to about 90%, up to about 80%, up to about 70%, up to about60%, or up to about 50% of the average diameter. In certain embodiments,the nanoparticles can have generally spherical or spheroidal shapes,although other shapes and configurations of nanoparticles arecontemplated.

Many embodiments provide that the metal alloy can include nanoparticlesat a volume percentage in a range of about 0.1% to 2%, about 0.25% to2%, about 0.5% or greater, about 1% or greater, about 2% or greater,about 3% or greater, about 5% or greater, about 6% or greater, about 7%or greater, about 8% or greater, about 9% or greater, about 10% orgreater, about 15% or greater, about 20% or greater, or about 25% orgreater, and up to about 30% or greater. As can readily be appreciated,any of a variety of nanoparticle concentration can be utilized asappropriate to the requirements of specific applications in accordancewith various embodiments of the invention.

Several embodiments provide that die cast metal alloys including (butnot limited to) aluminum alloys with less than 4% silicon contentexhibit desirable mechanical properties, thermal conductivity, andelectrical conductivity. The mechanical properties, thermalconductivity, and electrical conductivity are measured for as-cast metalalloys without post processing. Some embodiments provide a low volumepercentage of nanoparticles (from about 0.1% to about 2%) can besuccessfully applied to die cast the traditionally difficult orimpossible to cast aluminum alloys. Examples of such alloys include (butare not limited to) AA6061 (Al-1.0Mg-0.6Si-0.25Cu), AA6063(Al-0.7Mg-0.4Si), A206 (Al-4.5Cu-0.3Mg), AA7075 (Al-5.6Zn-2.6Mg-1.6Cu),and a modified AA7075 ((Al-5.6Zn-2.6Mg-0.65Cu) for natural aging. Thesedie casting alloys in accordance with several embodiments show good diecasting capability while achieve high strength and good ductility. Thestrength and ductility are measured for as-cast alloys, without postprocessing. In many embodiments, die cast AA6061 and other 6000saluminum alloys can offer ductility and/or elongation less than or equalto about 30%; or from about 20% to about 30%; or less than or equal toabout 20%; or from about 10% to about 20%; or less than or equal toabout 10%; and thermal conductivity of less than or equal to about 230W/mw; or from about 200 W/mw to about 230 W/mw; or from about 100 W/mwto about 200 W/mw; or less than or equal to about 100 W/mw, better thanother commercially available die cast Al—Si alloys (see Table 2 above).

Many embodiments provide high pressure die casting of 7000 seriesaluminum alloys. The die cast 7000 series aluminum alloys can open upapplication space for die casting high strength aluminum alloys.Modified AA7075 alloy may be capable of offering extreme high strengthby natural aging after die casting in accordance with embodiments.

The increased fluidity and hot cracking resistance of the nanoparticlemodified metal alloys in accordance with some embodiments enable theproduction of thin wall structures using high pressure die castingprocesses, due to the low silicon content of die cast metal alloys. Manyembodiments produce die cast metal part with a thickness between about0.2 mm to about 0.5 mm; or greater than or equal to about 0.5 mm.

Some embodiments provide that thermal conductivity of die cast metalalloys can be affected by the porosity. Normally high pressure diecasting of aluminum parts have porosity from about 3% to about 5%.Certain embodiments provide that the porosity of die cast nanoparticleinfused metal alloys may vary in different parts. The porosity of diecast parts can be improved in vacuum die casting or processoptimization.

Many embodiments provide good anodizing capability and quality of diecast metal alloys with nanoparticles. Traditionally, die cast aluminumalloys have high Si content. Anodizing high Si content alloys may makeSi stand out and turn the metal parts to gray or black. Thus, high Sicontent alloys may not be able to produce different colors viaanodizing. In several embodiments, metal alloys with nanoparticles haveSi content of less than 4 wt. % and can be anodized to produce variouscolor parts. Color can be determined by dyes used to color the surfaceporous oxide after chemical treatment. Some embodiments provide that anycolor can be applied to the die cast metal alloys. Metal alloys withnanoparticles can also be successfully anodized to various colors due tolow or no silicon effect.

Several embodiments provide that post processing can be applied to diecast metal alloys with nanoparticles, but not necessary. Normally highpressure die cast alloys do not want any solution treatment due toblistering effect. In some embodiments, post processing including (butnot limited to) T5 or natural aging can be applied. In certainembodiments, post processing including (but not limited to) T6 can beapplied to die cast metal parts with low or no porosity (such as aftervacuum high pressure die casting). As can readily be appreciated, any ofa variety of post processing treatment can be utilized as appropriate tothe requirements of specific applications in accordance with variousembodiments of the invention.

Many embodiments provide high pressure die casting processes with metalalloys infused with nanoparticles. In several embodiments, the metalalloys including (but not limited to) aluminum alloys, magnesium alloys,and zinc alloys, have silicon content of less than about 4 wt. %. A highpressure die casting process in accordance with an embodiment of theinvention is illustrated in FIG. 1 . The process 100 begins by preparingmetals and/or metal alloys with nanoparticles 101. In some embodiments,nanoparticles can be incorporated and dispersed uniformly in metalmatrix. In several embodiments, nanoparticles can have about 0.1 vol. %to about 2 vol. % in the metal alloys. Certain embodiments providenanoparticles can be made of materials including (but not limited to)metal oxides (e.g., alkaline earth metal oxides, post-transition metaloxides, and transition metal oxides, such as aluminum oxide (Al₂O₃),magnesium oxide (MgO), titanium oxide (TiO₂), yttrium oxide (Y₂O₃),magnesium aluminate (MgAl₂O₄), and zirconium oxide (ZrO₂)), non-metaloxides (e.g., silicon oxide (SiO₂)), metal carbides (e.g., transitionmetal carbides, such as titanium carbide (TiC), niobium carbide (NbC),chromium carbide (Cr₃C₂), nickel carbide (NiC), hafnium carbide (HfC),vanadium carbide (VC), tungsten carbide (WC), and zirconium carbide(ZrC)), non-metal carbides (e.g., silicon carbide (SiC)), metalsilicides (e.g., transition metal silicides, such as titanium silicide(Ti₅Si₃)), metal borides (e.g., transition metal borides, such astitanium boride (TiB₂), zirconium boride (ZrB₂), hafnium boride (HfB₂),vanadium boride (VB₂), and tungsten boride (W2B5)), metal nitrides(e.g., transition metal nitrides), core-shell particles, metals (e.g.,transition metals in elemental form such as tungsten (W)). Previous workhas described in details the preparations of nanoparticles mixed withmetal alloys (See, e.g., PCT Application No. PCT/US20/27775 to Li etal.; U.S. Pat. No. 9,322,084 B2 to Li et al.; U.S. Pat. No. 9,023,128 B2to Li et al.; the disclosures of which are incorporated herein byreferences by their entirety.)

The metals mixed with nanoparticles can be melted and further alloyed toform molten metal alloys with certain compositions 102. Aluminum alloysincluding (but not limited to) AA6061, AA6063, AA6069, AA2024, AA5083,AA7075, A206, A201, AA6013, AA2024, AA7034, AA7050, and AA7068, can beprepared for high pressure die casting. Many embodiments provide thatmetal alloys mixed with nanoparticles have less than about 4 wt. %silicon in order to improve mechanical properties, thermalconductivities, and anodizing capabilities of such alloys.

Die cavity can be prepared before injecting the molten metal alloys 103.The inside of the die mold can be sprayed with a layer of lubricant toease the release of cast metal parts. Molten metal alloys can beinjected into the die mold under a high pressure 104. Many embodimentsprovide that the pressure to inject molten metal alloy ranges from about30 MPa to about 100 MPa. In certain embodiments, the pressure can belower than about 30 MPa, or higher than about 100 MPa. In someembodiments, the pressure can be higher than 100 MPa. The pressure ismaintained until the casting solidifies. The die is then cooled with ahigh cooling rate 105. In several embodiments, the cooling rate canrange from about 100° C./s to about 300° C./s to solidify the moltenmetal alloy. In a number of embodiments, the cooling rate can be lowerthan about 100° C./s, or higher than about 300° C./s. Nanoparticles canimprove the fluidity and hot cracking resistance and reduce die stickingof metal alloys with low silicon content, thus render alloys with lessthan 4 wt. % silicon compatible with the high pressure injection processand the rapid cooling process. Once the metal alloy solidifies, themetal parts can be retrieved (not shown).

The die cast metal parts can be anodized to add desired colors 106.Anodizing can be optional. High silicon content in metal alloy mayappear gray or black after anodizing. In comparison, the nanoparticlesmodified metal alloys have silicon of less than 4 wt. % compared to thenormal 8 wt. %-10 wt. % silicon. The low silicon metal alloy inaccordance with many embodiments do not appear gray or black afteranodizing. Thus, the die cast metal parts with nanoparticle modifiedmetal alloys can be anodized to add any color of choice including (butnot limited to) red, blue, green, yellow, silver, gold.

Die cast aluminum alloy samples in accordance with an embodiment of theinvention are illustrated in FIG. 2A and FIG. 2B. FIG. 2A illustrates adie cast AA6061 alloy sample. The AA6061 alloy used in FIG. 2A is notmodified with nanoparticles. The die cast sample shows multiple cracklines 201. FIG. 2B illustrates a die cast AA6061 alloy modified withabout 1.0 vol. % TiC nanoparticles. The die cast sample has smoothsurface. The sample is anodized to obtain red color.

EXEMPLARY EMBODIMENTS

Although specific embodiments of systems and methods are discussed inthe following sections, it will be understood that these embodiments areprovided as exemplary and are not intended to be limiting.

Example 1: High Pressure Die Casting AA6061 Alloy

Many embodiments provide high pressure die casting of aluminum alloysincluding (but not limited to) high performance AA6061 alloy. In severalembodiments, AA6061 alloy can be modified with about 1.0 vol %nanoparticles including (but not limited to TiC nanoparticles. Table 4below lists properties of die cast AA6061 alloy containing about 1.0vol. % nanoparticles. The nanoparticle modified AA6061 alloy has as-castultimate tensile strength of about 205 MPa, yield strength of about 125MPa, elongation of about 16%, and thermal conductivity of about 140W/mk). Post processing can further improve the mechanical properties.After T5 treatment, the AA6061 alloy has ultimate tensile strength ofabout 226 MPa, yield strength of about 165 MPa, elongation of about 10%,and thermal conductivity of about 142 W/mk). After T6 treatment, theAA6061 alloy has ultimate tensile strength of about 353 MPa, yieldstrength of about 305 MPa, elongation of about 9%, and thermalconductivity of about 145 W/mk).

TABLE 4 Typical Properties of Die Cast AA6061 containing 1.0 vol %nanoparticles Ultimate Tensile Yield Thermal Strength StrengthElongation Conductivity Heat Treatment (MPa) (MPa) (%) (W/mk) As Diecast 205 125 16 140 T5 226 165 10 142 T6* (if air trapping 353 305 9 145is not an issue)

Die cast aluminum alloys including (but not limited to) AA6061 alloy canbe anodized to add any color of choice. Die cast parts of AA6061 showingvarious colors in accordance with an embodiment of the invention areillustrated in FIGS. 3A-3D. In FIGS. 3A-3D, the die cast AA6061 partscontaining about 1.0 vol % TiC nanoparticles. FIG. 3A shows the die castpart can be anodized to have gold color. FIG. 3B shows the die castaluminum part can be anodized to have red color. FIG. 3C shows the diecast part can be anodized to have silver color. FIG. 3D shows the diecast alloy can be anodized to be blue in color. The die cast metal partsshow smooth surface without cracks.

Example 2: High Pressure Die Casting A206 Alloy

Several embodiments provide high pressure die casting of aluminum alloysincluding (but not limited to) high performance A206 alloy. For A206alloy, nanoparticles allow much better fluidity and eliminate hotcracking to enable reliable die casting of this traditional-difficultdie casting alloys in accordance with many embodiments. The addition ofnanoparticles also improves die filling, part pressure tightness,strength and ductility. The die cast A206 alloy with nanoparticles canoffer strength of up to about 450 MPa, elongation of up to 15%.

DOCTRINE OF EQUIVALENTS

This description of the invention has been presented for the purposes ofillustration and description. It is not intended to be exhaustive or tolimit the invention to the precise form described, and manymodifications and variations are possible in light of the teachingabove. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical applications.This description will enable others skilled in the art to best utilizeand practice the invention in various embodiments and with variousmodifications as are suited to a particular use. The scope of theinvention is defined by the following claims.

As used herein, the singular terms “a,” “an,” and “the” may includeplural referents unless the context clearly dictates otherwise.Reference to an object in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.”

As used herein, the terms “approximately” and “about” are used todescribe and account for small variations. When used in conjunction withan event or circumstance, the terms can refer to instances in which theevent or circumstance occurs precisely as well as instances in which theevent or circumstance occurs to a close approximation. When used inconjunction with a numerical value, the terms can refer to a range ofvariation of less than or equal to ±10% of that numerical value, such asless than or equal to ±5%, less than or equal to ±4%, less than or equalto ±3%, less than or equal to ±2%, less than or equal to ±1%, less thanor equal to ±0.5%, less than or equal to +0.1%, or less than or equal to±0.05%.

Additionally, amounts, ratios, and other numerical values may sometimesbe presented herein in a range format. It is to be understood that suchrange format is used for convenience and brevity and should beunderstood flexibly to include numerical values explicitly specified aslimits of a range, but also to include all individual numerical valuesor sub-ranges encompassed within that range as if each numerical valueand sub-range is explicitly specified. For example, a ratio in the rangeof about 1 to about 200 should be understood to include the explicitlyrecited limits of about 1 and about 200, but also to include individualratios such as about 2, about 3, and about 4, and sub-ranges such asabout 10 to about 50, about 20 to about 100, and so forth.

What is claimed is:
 1. A metal alloy for high pressure die casting,comprising: a metal alloy selected from the group consisting of analuminum alloy, a magnesium alloy, a copper alloy, and a zinc alloy; andat least one type of nanoparticle dispersed in the metal alloy; whereinthe metal alloy comprises less than 4.0 wt. % silicon; and wherein themetal alloy is compatible with a high pressure die casting process. 2.The metal alloy of claim 1, wherein the metal alloy is selected from thegroup consisting of A201, AA2024, A206, AA2618, AA5083, AA6013, AA6061,AA6063, AA6069, AA7034, AA7050, AA7075, and AA7068.
 3. The metal alloyof claim 1, wherein the at least one type of nanoparticle is selectedfrom the group consisting of a metal oxide, a non-metal oxide, a metalcarbide, a non-metal carbide, a metal silicide, a metal boride, a metalnitride, and any combinations thereof.
 4. The metal alloy of claim 1,wherein the at least one type of nanoparticle has a structure of acore-shell particle.
 5. The metal alloy of claim 1, wherein thenanoparticle comprises less than 30 vol. % of the metal alloy.
 6. Themetal alloy of claim 1, wherein the nanoparticle comprises 0.1 vol. % to2 vol. % of the metal alloy.
 7. The metal alloy of claim 1, wherein themetal alloy comprises AA6061 and the nanoparticle comprises TiC, and theTiC nanoparticle comprises 1.0 vol. % of the metal alloy.
 8. The metalalloy of claim 1, wherein the high pressure die casting process uses apressure between 30 MPa and 100 MPa.
 9. The metal alloy of claim 1,wherein the high pressure die casting process uses a pressure greaterthan 100 MPa.
 10. The metal alloy of claim 1, wherein the high pressuredie casting process comprises a cooling step with a cooling rate between100° C./s and 300° C./s.
 11. A method for high pressure die castingcomprising: providing a metal alloy modified with at least one type ofnanoparticle, wherein the metal alloy comprises a silicon weightconcentration of less than 4.0%; melting the metal alloy and filling adie with the molten metal alloy under a pressure, wherein the pressureis compatible with the high pressure die casting process; and coolingthe die to solidify the molten metal alloy.
 12. The method of claim 11,further comprising anodizing the die cast metal alloy with at least onecolor.
 13. The method of claim 11, wherein the metal alloy is selectedfrom the group consisting of an aluminum alloy, a magnesium alloy, acopper alloy, and a zinc alloy.
 14. The method of claim 11, wherein themetal alloy is selected from the group consisting of A201, AA2024, A206,AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA7034, AA7050, AA7075,and AA7068.
 15. The method of claim 11, wherein the at least one type ofnanoparticle is selected from the group consisting of a metal oxide, anon-metal oxide, a metal carbide, a non-metal carbide, a metal silicide,a metal boride, a metal nitride, and any combinations thereof.
 16. Themethod of claim 11, wherein the at least one type of nanoparticle has astructure of a core-shell particle.
 17. The method of claim 11, whereinthe at least one type of nanoparticle comprises less than 30 vol. % ofthe metal alloy.
 18. The method of claim 11, wherein the nanoparticlecomprises 0.1 vol. % to 2 vol. % of the metal alloy.
 19. The method ofclaim 11, wherein the metal alloy comprises AA6061 and the nanoparticlecomprises TiC, and the TiC nanoparticle comprises 1.0 vol. % of themetal alloy.
 20. The method of claim 11, wherein the die cast metalalloy as formed has a elongation equal to or less than 30% and anultimate tensile strength greater than 500 MPa.
 21. The method of claim11, wherein the die cast metal alloy has a thickness of at least 0.2 mm.22. The method of claim 11, wherein the pressure is between 30 MPa and100 MPa.
 23. The method of claim 11, wherein the pressure is greaterthan 100 MPa.
 24. The method of claim 11, wherein the die is cooled witha cooling rate between 100° C./s and 300° C./s.
 25. The method of claim11, further comprising a post process of the die cast metal alloy. 26.The method of claim 25, wherein the post process is selected from thegroup consisting of: a T5 treatment, a natural aging treatment, and a T6treatment.
 27. A high pressure die cast metal part comprising: a metalalloy; and at least one type of nanoparticle dispersed in the metalalloy; wherein the metal alloy comprises less than 4.0 wt. % silicon;wherein the metal part is produced via a high pressure die castingprocess; and wherein the die cast metal part has a thickness of at least0.2 mm.
 28. The die cast metal part of claim 27, wherein the metal alloyis selected from the group consisting of an aluminum alloy, a magnesiumalloy, a copper alloy, and a zinc alloy.
 29. The die cast metal part ofclaim 27, wherein the metal alloy is selected from the group consistingof A201, AA2024, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069,AA7034, AA7050, AA7075, and AA7068.
 30. The die cast metal part of claim27, wherein the at least one type of nanoparticle is selected from thegroup consisting of a metal oxide, a non-metal oxide, a metal carbide, anon-metal carbide, a metal silicide, a metal boride, a metal nitride,and any combinations thereof.
 31. The die cast metal part of claim 27,wherein the at least one type of nanoparticle has a structure of acore-shell particle.
 32. The die cast metal part of claim 27, whereinthe nanoparticle comprises less than 30 vol. % of the metal alloy. 33.The die cast metal part of claim 27, wherein the nanoparticle comprises0.1 vol. % to 2 vol. % of the metal alloy.
 34. The die cast metal partof claim 27, wherein the metal alloy comprises AA6061 and thenanoparticle comprises TiC, and the TiC nanoparticle comprises 1.0 vol.% of the metal alloy.
 35. The die cast metal part of claim 27, whereinthe high pressure die casting process uses a pressure between 30 MPa and100 MPa.
 36. The die cast metal part of claim 27, wherein the highpressure die casting process uses a pressure greater than 100 MPa. 37.The die cast metal part of claim 27, wherein the high pressure diecasting process comprises a cooling step with a cooling rate between100° C./s and 300° C./s.
 38. The die cast metal part of claim 27,wherein the metal part is anodized with at least one color.
 39. A methodfor improving castibility of a metal alloy, comprising: incorporating atleast one type of nanoparticle into a metal alloy; wherein the metalalloy comprises less than 4.0 wt. % silicon; wherein the nanoparticlecomprises less than 30 vol. % of the metal alloy; and wherein the metalalloy is compatible with a high pressure die casting process.
 40. Themethod of claim 39, wherein the metal alloy selected from the groupconsisting of an aluminum alloy, a magnesium alloy, a copper alloy, anda zinc alloy.
 41. The method of claim 39, wherein the metal alloy isselected from the group consisting of A201, AA2024, A206, AA2618,AA5083, AA6013, AA6061, AA6063, AA6069, AA7034, AA7050, AA7075, andAA7068.
 42. The method of claim 39, wherein the at least one type ofnanoparticle is selected from the group consisting of a metal oxide, anon-metal oxide, a metal carbide, a non-metal carbide, a metal silicide,a metal boride, a metal nitride, and any combinations thereof.
 43. Themethod of claim 39, wherein the at least one type of nanoparticle has astructure of a core-shell particle.
 44. The method of claim 39, whereinthe nanoparticle comprises 0.1 vol. % to 2 vol. % of the metal alloy.45. The method of claim 39, wherein the metal alloy comprises AA6061 andthe nanoparticle comprises TiC, and the TiC nanoparticle comprises 1.0vol. % of the metal alloy.
 46. The method of claim 39, wherein the highpressure die casting process uses a pressure between 30 MPa and 100 MPa.47. The method of claim 39, wherein the high pressure die castingprocess uses a pressure greater than 100 MPa.
 48. The method of claim39, wherein the high pressure die casting process comprises a coolingstep with a cooling rate between 100° C./s and 300° C./s.